Electroplating



Patented Oct. 6, 1931 j UNITED STATES,

PATENT OFFICE LEON-B. WESTIBROOK, 0F CLEVELAND HEIGHTS, OHIO, ASSIGN OR, IBY MESNE ASSIGN- MENTS, TO THE GRASSELLI CHEMICAL COMPANY, OF CLEVELAND, OHIO, AIJOB- PORATION OF DELAWARE ELEGTROPLATING No Drawing.

Application filed July 11,

1927. Serial No. 205,038. I

It is a well-known practice to add certain The sulfonated oil is usually introduced table oils when added to electroplating baths produce very desirable and unique results. This is particularly the case with alkaline cadmium-cyanide baths, and if such cadmium baths contain small amounts of nickel salts as described in my co-pending application Serial No. 150,376, Patent 1,681,509,

Aug. 21, 1928, filed November 23, 1926, I have found that the addition of sulfonated oils' produces platings' which are smoother,

denser, and brighter than any other cadmium plates so far known.

The, most common available sulfonated oil useful in my invention is the Turkey red oil,'or sulfonated castor oil which is used in tremendous quantities in the textile industries. Other sulfonated oils, such as sulfonated cotton seed oil, sulfonated corn oil, etc., were found to have equally as good brightening effect.

Sulfonated castor oil is quite often used in admixture with water insoluble solvents such as carbontetrachloride, hydronapthalenes, hydrocresoles, etc., such mixtures being soluble in water and are used as detergents and washing agents. Such mixtures can likewise be used as addition agents, though in most cases they will have no additional separate advantage over straight su-lfonated castor oil when added to an electroplating bath. I

The amounts of sulfonated vegetable oil to be added to an electroplating bath can be varied to a considerable'extent. I have found, for instance, that in a cadmium cyanide bath containing the requisite other electrolytic salts, 0.5% tov 3 or 4% of the bath of Turkey red oil will give remarkable results; amounts above 1% are not detrimental but give no better results than smaller amounts.

when used as a finish plate or as an undercoat for a nickel plate. The cadmium coat obtained from the above bath is also bright, dense, and white when deposited on any surface. 7

It is often advisable in the commercial application of electroplating to provide the manufacturer with a ready prepared ,dry mixture of the electroplating salts, from which he can prepare his baths by merely dissolving such a compounded mixture in water.

Sulfonated vegetable oils can easily be incorporated into such ready-prepared mixtures.

Monopole soap, for instance, is a solid form of sulfonated castor oil and can be added while the other components are being mixed. The liquid sulfonated vegetable oils are easily absorbed on the constituents of the plating compound mixture, and the product obtained is practically dry. It is also possible to prepare cadmium salts or compounds of the sulfonated oils. This can be achieved, for instance, by adding a cadmium salt, such as the sulfate, to a solution of a sulfonated oil in caustic soda. The cadmium compound of the sulfonated oil separates and can be recovered. This is, in the case of sulfonated castor oil, a white solid which mixes readily with the other electroplating components.

The composition of such compounded electroplating salts can be varied within'wide limits, but it will be found that the presence therein of a sulfonated vegetable oil, particularly in connection with cadmium plating salts containing small amounts of nickel salts, produces plating baths from which exceptionally bright, dense deposits are obtained.

The following is a typical example of such compounded electrolyte which was found particularly valuable:

Sodium cyanide- 120 parts by weight Cadmium hydroxide 48 Sodium sulfate 6O Cryst. nickel sulfate- 1. 5 Sulfonated castor oil 12 It is a dry powder, easily soluble in water.

I claim:

1. A cadmium-cyanide electroplating bath containing a sulfonated vegetable oil in addition to the requisite cadmium, cyanide, and other electroplating compounds.

2. A cadmium-cyanide electroplating bath containing sulfonated castor oil and a small amount of a nickel salt in addition to the requisite cadmium, cyanide, and other electroplating compounds.

3. A composition of matter adapted for use in the preparation of an electroplating bath consisting of a substantially dry mixture comprising a cadmium compound, and a sulfonated vegetable oil.

4. A composition of matter adapted for use in the preparation of an electroplating bath consisting of a substantially dry mixture comprising a cadmium compound, a small amount of a nickel salt, an alkali metal cyanide and sulfonated castor oil.

5. A composition of matter adapted for use in the preparation of an electroplating bath consisting of a mixture of 48 parts cadmium hydroxide, parts sodium cyanide, 60 parts sodium sulfate, 1.5 parts crystallized nickel sulfate, and 12 parts Turkon oil.

6. Process which comprises electrodepositing cadmium from a cadmium-cyanide electroplating bath containing a sulfonated vegetable oil in addition to the requisite cadmium, cyanide, and other electroplating compounds.

In testimony whereof, I affix my signature.

LEON R. VVESTBROOK. 

